Numerous spectacle designs are currently available, many of which feature frames made entirely of plastic material, or made partly of plastic and partly of metal elements, or made entirely of metal elements; and the lenses are normally supported on a portion of the frame fitted tightly about the edge of the entire lens, or a portion of the frame is connected to the lenses by means of nuts and screws engaging holes formed in the lenses.
In such designs, the bridge connecting the lenses presents two plates which rest laterally on either side of the nose to support the spectacles at the front. In some designs, the plates are fixed and formed in one piece with the frame, or are movable and fitted to the bridge by an articulated joint to enable them to adapt and rest comfortably on either side of the nose.
In both cases, besides being unsightly, the plates eventually become a source of discomfort with prolonged use, and, by virtue of their shape, are easily soiled, thus further impairing their overall appearance.
European Patent n. 256.098-B1 relates to a spectacle mount made of metal wire, and wherein the hinges of the lateral arms each comprise a fixed straight portion connected to the lens by a bent wire portion and forming the hinge pin, and a movable portion connected to the lateral arm and comprising a portion of coiled wire rotatable about the fixed pin. The free end of the coiled wire portion acts as a stop for arresting rotation of the coil, and hence of the lateral arm, by contacting the bent wire portion; the bent wire portion joining the straight portion or fixed pin to the lens is bent radially outwards once per end, with the bends lying in planes perpendicular to each other, and continues towards the lens with a U-shaped bend lying in a plane substantially parallel to the normally vertical fixed pin, and which is designed to be inserted elastically into a corresponding opening formed close to the outer edge of the lens.
Similarly, the bridge connecting the two lenses is fitted to each lens by a wire portion bent into a U and inserted elastically into an opening formed close to the inner edge of the lens.
Two movable plates for support on either side of the nose are fitted in freely adjustable manner to respective wire curls integral with the connecting bridge.
The above state-of-the-art mount nevertheless presents several drawbacks. Forming openings large enough to house the two wire portions forming the bend means removing a large amount of material, which, besides the time and cost involved, also weakens the lens. Moreover, since the bend, once inserted inside the opening, works by expanding elastically, the lenses, which are normally made of highly rigid, fragile material with a low safety load, are subjected to dangerous tensile and bending stress. To reduce the risk involved, large openings are therefore formed closer to the center of the lens, which, besides noticeably invading the field of view, creates discomfort to the wearer, especially in the case of thick lenses, by creating highly noticeable opaque or reflecting walls. Also to be taken into account is the accumulation of soil in the gap between the wires and the opening, which impairs the appearance of the spectacles which must therefore be disassembled and cleaned periodically.